Sanitary napkin



D 18, 1951 D. w. BEERY ETAL SANITARY NAPKIN Filed May a, 1947 21 QDTTER:ELVIN R- IN R M JfiMES 'J.EBERL DONALD 1 WBEERY 2 m W Patented Dec. 18,1951 SANITARY NAPKIN Donald W. Beery, New Brunswick, James J. Eberl,Bound Brook, and Alvin R. Ingram, New Brunswick, N. J assignors toJohnson & Johnson, a corporation of New Jersey Application May 8, 1947,Serial No. 746,644

2 Claims. (Cl. 154-416) This invention relates to an improved sanitarynapkin and to a method of producing the same. More particularly itrelates to a sanitary napkin having a gauze wrapper that is sealed by afilament having adhesive properties.

Sanitary napkins ordinarily comprise a body of one or more layers ofmedia having absorbent properties; the media are usually cellulosic innature and may be cotton or paper and may also include one or morelayers of material which has limited absorbency. In one type of sanitarynapkin the layers of material having absorbent properties are wrapped orenveloped in a sheet of gauze. The gauze acts to hold together thevarious layers of the absorbent materials constituting the pad as wellas to provide a means I for attaching the pad to the garment. The

gauze is usually simply folded over the pad and is ordinarily of such awidth that there is a substantial overlap which serves to hold the gauzein place by means of friction at the overlap; such a substantial overlaphas been found to be essential in an unsealed napkin. A napkin having asmall overlap has the disadvantage that the gauze wrapper readily comesapart, for which reason it has been customary to use a gauze ofsuflicient width to provide a substantial overlap, which in someinstances is as wide as the napkin itself. The expedient of having asubstantial overlap as a means of sealing the gauze covering isinefllcient because it requires the use of a large amount of gauze.

A general object of this invention is to provide a sanitary napkin inwhich the gauze wrapper surrounding the absorbent material will notseparate and become detached from the absorbent material.

Another object of this invention is to provide a method for sealing thegauze wrapper of a sanitary napkin.

A further object of this invention is to provide a sanitary napkinhaving a minimum overlapping of the gauze wrapper.

Still another object of this invention is to provide a sanitary napkinhaving the gauze wrapper sealed at the lapped edges.

Another and further object of this invention is to provide a sanitarynapkin having a gauze wrapper sealed at the lapped edges which isreadily disposable.

A more specific object of this invention is the provision of a sanitarynapkin in which the gauze wrapper is sealed at the lapped edges and inwhich the seal is inexpensive, flexible, non-irritating. and non-tackyat ordinary temperatures.

Other objects of the invention will appear from the followingdescription and accompanying drawing as well as from the appendedclaims.

It has now been discovered that a sanitary napkin, having a minimumoverlapping of the gauze at the lapped edges, and which overcomes thedifliculties of the prior art may be made by sealing the gauze wrapperof the sanitary napkin at the lapped edges by means of a thermoplasticfilament that is tacky at elevated temperatures but substantiallynon-tacky at ordinary temperatures. As the filament is applied to thegauze wrapper at the lapped edges, it is heated at an elevatedtemperature so that by reason of its thermoplastic nature it is soft andtacky. Due to the open weave character of the gauze the adhesivefilament penetrates both layers of gauze and after the filament hascooled, the two layers of gauze are firmly attached at 'the overlap.

A natural or synthetic fiber may be used as a base material in formingthe filament and in this embodiment of the invention the fiber isimpregnated with an adhesive composition that is tacky at elevatedtemperatures but substantially non-tacky at ordinary temperatures and inthe preferred form of the invention a natural fiber such as cotton,wool, linen, and the like is used. A thermoplastic synthetic resinousfilament composition having adhesive properties and which is tacky atelevated temperatures but substantially non-tacky at ordinarytemperatures may also be used.

It is preferred that the filament be colored either by using a dyedfilament or by adding a color to the adhesivecomposition. By having thefilament colored, the side worn away from the body is readilyidentified.

In the practice of this invention, the components of the sanitary napkinhaving absorbent properties are assembled and a gauze wrapper is placedaround the assembled components with the opposite edges of the wrapperoverlapping slightly. A filament tacky at elevated temperatures butsubstantially non-tacky at ordinary temperatures or a cotton threadimpregnated with an adhesive material which is tacky at elevatedtemperatures and substantially non-tacky at ordinary temperatures, andwhich preferably contains a dye, is then placed longitudinally incontact with the overlapping portion of the gauze in a linear path whilethe filament is at an elevated temperature. The adhesive penetratesthrough the two layers of gauze and upon cooling causes a sealing of thetwo layers of gauze at the overlap. In the preferred practice of thefilament is placed on top of the first layer of gauze at the overlap andstrikes through to the second layer of gauze and upon cooling the twolayers of gauze are sealed tosether.

The adhesive filament should have the char: acteristics of tackiness atelevated temperatures and non-tackiness at ordinary temperatures,sufficient bonding strength to form a strong bond between the two layersof gauze at the lapped edges, low cost, stability at the elevatedtemperature at which it is heated when applied, low viscosity at theapplication temperature, sufficient tack at the application temperaturewhen semi-molten to adhere to the gauze wrapping, ready solidificationon cooling and good flexibility at room temperatures. An additional andimportant feature of the adhesive filament is that, when used to seal agauze wrapper, the bond is strong enough to prevent the gauze wrapperfrom opening during ordinary use but is of such a strength that thewrapper may be readily opened, thus allowing the absorbent, comprisingcellulosic material, pad to be readily disposed of.

The desired characteristics in the filament or composition adhesive areobtained by a composition comprising a mixture of a thermoplastic resincontaining composition and diluent such as a wax that is substantiallyimmiscible in said resin at ordinary temperatures. The proportion ofdiluent such as a wax used is so adjusted that the mixture invention theis substantially homogeneous when molten, but.

heterogeneous when solid. It is not necessary however that the adhesivecomposition be in the form of a solution when at an elevated tempera-.ture; it may be a dispersion or a partial dispersion with somesolution. when cooled to ordinary temperatures the wax bleeds out of thecomposition and forms a superficial wax coating on the surface of theresin, thereby masking any residual tackiness which the thermoplasticresin containing composition may have at normal temperatures.

Resins which have been found suitable for use in filaments and adhesivecompositions include ethyl cellulose, cellulose acetate butyrate,polyvinyl acetate, vinyl acetate-chloride copolymer,

polyvinyl butyral and zein. Parafiin wax and other waxes which arechemically inert, such as common vegetable wax, beeswax, and the like,have been found suitable for use as diluents in compounding the adhesivecomposition or filament.

The diluent such as a wax is an important component of the mixturebecause it exerts a viscosity reducing and diluting action on the resincontaining composition when the mixture is molten. Since, however, thediluent wax is substantially incompatible with the resin containingcomposition at room temperatures, it separates out and migrates to thesurface of the mixture, forming a superficial coating thereof, thusminimizing or masking any tacky properties that the resin containingcomposition may have at the temperature at which the sealed napkin-isused. Another reason for having a diluent such as a wax in the filamentor adhesive composition which is incompatible with the resinous materialis that it gives a smooth feel and nonabrasive character to the cooledfilament.

When the diluent used is a paraflin wax, it is desirable to employ ablending agent which is mutually compatible with the resin and theparafiin wax; hydrogenated methyl abietate is a suitable blending agentfor this purpose andacts as a Ethyl cellulose parts- 25 Hydrogenatedmethyl abietate do 45 Paraffin w do 30 Menthyl phe do 3 Oil soluble dyeltrace This composition is particularly suited for use because it can beconverted by heating into a fluid form which may be readily applied to afibrous filament and which will cool quickly to form a fiexible,non-tacky coating of the filament. A filament coated with the abovecomposition can be placed on the gauze overlap of the napkin at thelapped edges while the adhesive composition is in a fluid form and theadhesive composition will then penetrate through the two layers of gauzewrapping at the lapped edges and upon cooling and solidification of theadhesive composition, effectively seal the gauze wrapping.

In the accompanying drawing there is disclosed one form of apparatusdesigned to carry out the various objects of the invention, but it is tobe understood that the invention is not confined to the exact featuresin the drawing since various changes may be made within the scope of theclaims which follow.

In the drawing:

Fig. 1 is a perspective view of a sanitary napkin according to oneembodiment of the invention, showing the napkin open at one end.

Fig. 2 is a flow sheet showing the apparatus and processes used forconstructing the napkin.

Referring particularly to Fig. 1, the napkin comprises an elongated padl0 having rounded ends and composed of flexible absorbent cellulosicmaterial, wrapped in a sheet of gauze l2, the gauze being substantiallylonger than the pad and overlapping the pad to a small amount. FilamentI3, comprising a cotton thread impregnated with an adhesive compositionand in the preferred form containing a dye, is spaced in approximatelythe middle of the overlap formed by the gauze wrapping. It is preferredthat the absorbent material have one surface composed of an absorbentmaterial having relatively less absorbency than the other surface.

In Fig. 2, gauze from gauze roll I5 is passed into a unit I! in whichcellulosic pads are combined with the gauze in such a way that the gauzeis wrapped around the pads and that the pads are spaced at regularintervals in the gauze wrapping. The method for combining the cellulosicpads with the gauze is not shown. The pads, spaced in the continuousstrip of gauze, are driven between a belt I8, which is preferablyfabricated of canvas or leather, and a leather belt I. The leather beltI6 is faced with a material to which the heated filament will notadhere. Resinous materials have been found suitable for facing the beltand plasticized vinyl acetate chloride copolymer has been foundparticularly suitable. If belt I8 is not faced with a resinous materialthe adhesive filament adheres to the belt and it is necessary for properfunctioning of the process that the said belt be faced with a materialwhich does not adhere to the gauze by the canvas or leather belt it,which belt is carried on the surface of pocket wheel 26 and roller 21.Pocket wheel 26 is constructed so that the cellulosic pads fit into thepockets.-

The pads are subjected to pressure between belt i8 and belt l5 and thesemi-molten adhesive composition impregnated in the filament or thread25 is pressed through the overlapping layers of gauze by the pressureexerted, thus sealing the gauze wrapping at the Overlap. The continuousstrip of gauze, containing cellulosic pads at intervals, proceeds to acutter (not shown) and is there cut into lengths which are illustratedin Fig. 1.

In the preferred embodiment of the invention, as illustrated by thedrawing and described in conjunction with the detailed descriptionabove, a filament comprising a fiber or thread coated with an adhesivecomposition is used to seal the gauze wrapper but it is alsocontemplated that a filament composed of a resin containing com--position and wax as the basic ingredients may be used and in this lastembodiment the machine used to manufacture a sanitary napkin, sealed atthe lapped edg s. would be only slightly modified from the machineillustrated by the drawings: the adhesive pct 24 would be replaced by aheating unit to preheat a preformed filament comprising a resincontaining composition and a diluent such as a wax.

It is further contemplated that an adhesive composition, containingaresin and a diluent such as a wax, could be printed, while in a moltenstate, longitudinally in a linear path onto the gauze overlap of anassembled napkin.

The term "gauze" as used in this specification refers to woven andnon-woven fabrics.

It will be apparent to those skilled in the art that the principalobjects of the invention have been accomplished and that various changesand modifications may be made in the embodiment of the invention hereindisclosed. It will therefore be appreciated that the disclosures hereinmade are illustrative only and that the invention.

is limited only by the appended claims.

What is claimed is:

1. In a method of manufacturing a sanitary napkin having a cellulosicpad and a gauze Number Name Date 1,824,285 Matson Sept. 22, 19312,064,292 Charch Dec. 15, 1938 2,086,757 Williams July 13, 19372,142,039 Abrams et al. Dec. 27, 1938 2,193,188 Bradley Mar. 12, 19402,215,760 Ledrich Sept. 24, 1940 2,230,792 Billing Feb. 4, 19412,262,275 Fourness et al Nov. 11, 1941, 2,290,563 Kauppi July 21, 19.42.2,306,399 Menzel Dec. 29,19 2

2,331,355 Strongson Oct. 12, 1943 2,348,039 Ulrich May 2, 1944 2,394,101Phillips Feb. 5, 1946 2,408,508 Canavan Oct. 1,1948

FOREIGN PATENTS Number Country Date 542.869 Great Britain Jan. 29, 1942683,211 France Feb. 25, 1930- 8 wrapper with lapped edges: theimprovement which comprises the steps of placing a heated filament whichis tacky at elevated temperatures and substantially non-tacky atordinary temperatures at the locus of the said lapped edges and on topof the first layer of gauze of the lapped edges so that it extendslongitudinally along the pad in a linear path, and pressing said heatedfilament against the surface of the gauze wrapper.

2. In the method of manufacturing a sanitary napkin having a cellulosicpad and a gauze wrapper with lapped edges; the improvement whichcomprises the steps of impregnating a filament with a thermoplasticcomposition comprising ethyl cellulose, hydrogenated methyl abietate,paraffin wax, and a dye in which the wax is compatible with a mixture ofethyl cellulose and hydrogenated methyl abietate at elevatedtemperatures but at least partially incompatible therewith at ordinarytemperatures and in which the wax is present in an amount such that itmigrates to the surface of the said filament when the mixture passesfrom the semimolten to the solid state, placing said impregnatedfilament at the locus of the said lapped edges and on top of the firstlayer of gauze of the lapped edges so that it extends longitudinallyalong the pad in a linear path, and pressing said heated filamentagainst the surface of the gauze wrapper.

DONALD W. BEERY. JAMES J. EBERL. ALVIN R. INGRAM.

anrnanncns man The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

